- Geographic information (lat, long) is supported, and specifically I see index handling for MultiPolygon, Polygon, Point, types. geo tutorial
- dgraph is a very different architecture than neo4j, so it is probably hard to compare apples to apples here. But the data is indexed with a geo index, so that will be as fast as many of the other indices available.
- An s2 index implementation is what is used to index the geometry data. (code)